You will need to sign on with your LLLID (La Leche League ID) before you can post. If you have never claimed your LLLID, create your LLLID now. To sign in, click the LLLID Sign On button in the upper right corner. Enter your LLLID Alias and click the button again.

Excess Lipase vs Chemical Oxidation

My daughter is currently 4 months old and I recently pulled some frozen breast milk that is about 2 months old from my freezer. When it was almost all the way defrosted I smelled it and it smelled bad. More sour than soapy. I tasted it and it was horrible. All 3 bags I pulled were like that. I also noticed this smell and bad taste when my milk is in the fridge for more than 48 hours. At first I thought it was excess lipase. So yesterday I scaled my milk and then put it in the fridge to test. After 24 hours it not only smelled bad but also had some small chunks in it. I threw it out. So does this mean it is a chemical oxidation issue? I am following proper pumping and storage procedures. If it is chemical oxidation, is the milk bad for baby? She actually drank the bad smelling milk yesterday and seemed fine. I only gave it to her because I thought it was excess lipase and I know that is fine for the baby as long as she will drink it.

Also, do I need to drink distilled water or will filtered water be ok? There seems to be a lot of info on excess lipase but not chemical oxidation.

Re: Excess Lipase vs Chemical Oxidation

Also, one more thing. When I scalded my milk it did boil. I was not watching close enough. Could that have caused it to go bad? I keep reading posts where mothers refer to their milk as "sour" and not "soapy." Can excess lipase cause sour tasting milk? This whole issue seems so confusing. I wish there were a better way to tell.

Re: Excess Lipase vs Chemical Oxidation

Welcome to the forum!

The first thing I have to say is that this is hands-down the most scientifically interesting question I personally have seen on the forum this year! I didn't even realize that oxidation was something that could reasonably happen to milk, but now that I realize that it is, I wonder why more people don't know about it, and whether some of the problems ascribed to excess lipase could actually be due to oxidation.

Okay, so the best link I found on milk oxidation was this: http://www.gov.mb.ca/agriculture/liv.../cda20s02.html Like most information about milk, it's tailored to the dairy industry. But it does suggest that a) oxidized milk will taste of ketones and aldehydes (more googling suggests that these compounds can impart a taste which may be sweet, metallic, soapy, and/or more), b) that consumption of oxidized milk poses no health risk and is exclusively a taste issue, and c) that there are a lot of potential variables that you can control which may eliminate the oxidation problem.

I have no idea how to detect the presence of aldehydes without doing some real chemistry. But ketones might be detectable with an item which you can purchase at the drug store: ketostix. Diabetics use them to detect ketones in their urine, and they might work on milk, as well. But that's just a guess- I'd talk to a chemist for the real answer.

It seems like the first variable to control is light. So you might try storing your milk in dark-colored, opaque containers. There are a lot of stainless steel bottles on the market, but they tend to be expensive! If you don't want to drop a ton of money on bottles, you might try storing your milk in an ordinary transparent container, but keeping that container inside a dark box or something.

If light isn't the issue, then you're looking for over agitation/aeration of the milk (too much shaking, perhaps? or a leaky valve in your pump?) or chemical residues in the containers, or in your diet. To control the chemical residue in the container aspect, it looks like you'd want to be careful about washing your bottles and pump parts, maybe even to the point of using distilled water if your tap water is highly chlorinated, very low pH (acid), or contains a lot of iron, copper, or sulfur.

Finally, if the cause of the oxidation is not light, not aeration, and not a residue in your containers, then you're looking at your diet as a potential cause. If you were a cow, it looks like you would want to consume more vitamin E, fiber, and selenium, and lower amounts of unsaturated vegetable oils (replacing them with animal fats) and legumes, and you would want to start drinking filtered water, and potentially replace any water pipes with plastic tubing. But you're not a cow- you are your baby's entire food source! I would consult a doctor before taking extra vitamin E and selenium, since those are potentially toxic in the wrong dosages. The other stuff is pretty much harmless, with the exception of eating more saturated fats... But hey, you have plenty of time in your life to eat healthy, so I figure you might want to enjoy your butter and cheese now.

Re: Excess Lipase vs Chemical Oxidation

Thanks for the info. This is the most I have seen on the oxidation issue. And yes, I do shake it a lot so I will stop that. It seems to be a habit when I see the milk separate. I am trying to scald some more milk. I heated some up today but did not let it boil and it is in the fridge now. I am going to see how long it takes before it goes sour. At least I know that feeding it to baby is not bad. I dont know how she swallows it!

I am also going to store the pumped bottles in a tote to keep any light from hitting it.

I keep coming bad to the same question about the taste. Many moms on here posted their milk was sour and disgusting. Would excess lipase taste sour or just soapy? Thanks again for all your info!

Re: Excess Lipase vs Chemical Oxidation

I just thought I would update everyone on my tests. I scaled my milk at 160 degrees for 15 seconds then cooled in the fridge and froze some. The milk in the fridge was NOT sour after 4 days. My milk turns sour after 36 - 48 hours. I defrosted the frozen milk after 2 weeks and it was NOT sour. This leads me to believe I have excess lipase and not chemical oxidation. I do not know why my milk tastes so gross but it was sour and not soapy. It made me gag! Anyway, I hope this post can help someone else with the same questions I had. My best advice is to try scalding your milk and see if that works. If is doesnt then you may have a different problem.